In recent years, many large circulation periodicals have appeared which require rapid handling of portions of the periodicals consisting of signatures which are gathered for stitching, trimmed, bundled for minimum shipping costs, and shipped. A typical operation utilizes a multitude of packer boxes, each of which receives signatures seriatim from a signature supply means, opens each signature, and drops the signatures successively to straddle a gathering chain that runs in front of the packer boxes and carries the complete collection of gathered signatures to the stitcher. Moreover, because of the need for highly efficient plant operations, there has been a constant effort to increase the speed at which machines operate which has required the development of new techniques for handling the signatures at all stages of the binding process.
In addition to high speed operation, many large circulation periodicals are now demanding a degree of flexibility that has been heretofore considered impossible. This is particularly true, for instance, where the periodical wishes to produce a number of different versions of books by feeding different combinations of signatures to form such books, but this must be done without significant reduction in the cyclic rate of operation that would otherwise decrease plant efficiency thereby increasing costs while possibly failing to accommodate the high volume presently produced by the U.S. printing industry which requires that the most efficient possible use be made of manpower, equipment and plant space. Further, in order to avoid any increase in costs that might otherwise be attributable to new equipment, the equipment to achieve the aforementioned objectives should be relatively inexpensive and compatible with normal bindery lines.
As an additional problem, it has been widely recognized in the printing industry that mechanical calipers require significant make-ready time that decreases the efficiency of plant operations. This is particularly true for selectively gathered or customized books where there may typically be a large number of versions of a book requiring a large number of settings for the conventional mechanical caliper. As the need for flexibility has increased, there has been a corresponding recognition of the desirability of eliminating the use of a mechanical caliper while maintaining high quality production on a binding line.
The present invention is directed to overcoming one or more of the foregoing problems and achieving one or more of the resulting objects.